it also pints out how far off some bodyfat calculators are. for example In the picture in my avatar I was estimated at between 12% and 14% i think. this gave me a LBM of (at the time) of about 160lbs. Jules in the pics is at about 9-10% and 175, putting him at a smaller LBM than I am in the Avatar... there is no way on this earth I am carrying more muscle in that pic than he was.
How many time do you see people saying they are 15% bf and 220lbs ??? thats a LBM of 187lbs which is pretty close to natural potential for someone of average height. for example Clarence Ross (Mr American 1945) was 5'10" and 185lbs at about 10% body fat...
Moral of the story, dont worry about what bf% you are at, just pick a way of testing it and make sure it is moving in the right direction, other wise you are gonna go mad thinking why you dont look like Mr America when you have 'apparently' got more LBM than them AND a lower body fat